Gem is a comprehensive electromagnetic gyrokinetic delta-f particle code
that includes the full dynamics of gyrokinetic ions and drift-kinetic
electrons. Magnetic perturbations perpendicular to the equilibrium field
are fully modeled. The simulation is useful for studying well-magnetized
plasma physics and is especially powerful because it is accurate at very-low
fluctuation levels. Electron-ion collisions are included as well as the full-capability
to model general axisymmetric toroidal equilibria.